List the imperial cities of the classical cities of the classical civilizations/empires and describe their purpose/importance.

These are the Imperial Cities during the Classical Civilizations:
Persepolis- it was constructed under the rule of King Darius the Great, Persepolis or "Parsa"is the capital of Persian Empire. This was built for the people in Persia where it could be a place for them to defend from their enemies and could be a place to worship their king.
Chang'an- played an important role in the in the beginning of the Silk Road
and a major religious center under Tang dynasty.
Pataliputrap- trade capital 
Athens- had great work on stones and sculptures that represent many of the Gods from Greek mythology.
Carthage- new center of Phoenician trade
Rome-  largely known for its engineering and for its architect
Alexandria-  had access to many pure elements including gold, silver, iron, copper, tin lead, mercury, sulfur, arsenic, and carbon.
Constantinople-  became the center of Greek classics and Christian ideals.
Teotihuacan- Religion was the main aspect of the societies and from it, politics, science and culture were derived